With the Philips DAC-960 Philips, acknowledged master-craftsman of Compact Disc, set the standards for the future of Digital Audio. This is a world first - a 3-in-1 unit for digital audio signal processing featuring: a digital source selector which handles multiple sampled inputs at 32. 44.1 and 48 kHz: a Reference Standard 16-bit quadruple oversampling and D-to-A converter, an 'audiophile quality' analogue control amplifier.
Reference Standard' Converter Unit with:
- Digital Source Selector
- 'Reference Standard' D/A converter TDA1541
- Control (Pre-) Amplifier
- Studio Quality Engineering
- 3 separate power supplies
- Automatic multi-sampling at 32, 44.1 and 48kHz
- Enhanced digital filtering
- Dual, high-linearity, 16-bit digital-to-analogue converter TDA1541
- Optical and electrical digital inputs
- Precision analogue filters
- 'Absolute Phase' control
- Balanced, direct and variable analogue outputs
- Digital monitor output
- High-quality headphone amplifier with volume control
High levels of performance
The Philips DAC-960 offers extremely high levels of performance for all the present and projected digital audio systems: the firmly-established Compact Disc system, the soon-to-arrive Digital Audio Tape (DAT) system, and the proposed Satellite Broadcasting standards. Three standardized digital inputs are provided. one optical and two electronic. They offer optimal coupling to all available and proposed digital audio sources, with automatic sampling-frequency selection.
The combination of enhanced digital filtering, high-linearity 16-bit DA conversion and precision analogue filtering guarantees uniquely high standards of audio signal with a choice of balanced, direct and variable outputs. A digital monitor output and variable-level headphone output are also featured. Studio quality electronic and mechanical engineering takes care that each of these outputs in its own way delivers every last detail of digital audio performance. Here is a design concept dedicated to providing the highest-ever standards for sound reproduction.
Optical digital input
The Philips DAC-960 optical input featuring an optical fibre cable and photo coupler. is compatible with the digital optical output of the Philips Compact Disc players and most other digital optical sources. Optical coupling has the big advantage that there is no signal loss, no earth loop, and no possibility of electromagnetic or electrostatic interference. This ensures that a very pure, noise-free digital signal is delivered to me converter input
Digital output
A standard 75-ohm digital output provides for DAT monitoring of connection of other digital signal processors.
Two electronic digital inputs
The two 75-ohm digital electronic inputs are compatible with all standard-output digital audio sources.
Sampling-frequency autolock
For Compact Disc and DAT (playback only the sampling frequency is 44.1 kHz. OAT (recording/playback) and Satellite Broadcasting systems use 32 kHz or 48 kHz. But no matter which type of source is connected to whatever input the DAC 960 input circuit automatically locks on to the correct sampling frequency which is then indicated on the display. as soon as an input is selected. There is no need for manual switching, and no possibility of error.
Enhanced digital filter and dual 16-bit digital-to-analogue converter TDA1541 The Philips DAC-960 incorporates an enhanced version of the quadruple oversampling digital filter specially developed and selected for Philips Compact Disc players. The oversampling technique has proved so good that it is being increasingly adopted by others manufacturers. This enhanced version features improved signal-to-noise ratio, complete suppression of passband ripple and extra stopband attenuation.
Three photo couplers are used to link digital filter and D- to A-converter chips optically in order to ensure absolute noise-free digital signal transfer.
The single DAC chip, also specially developed for Philips Compact Disc players, is selected for high specification. It incorporates separate, high-linearity 16-bit converters for left and right channels. This ensures very low distortion conversion, with no multiplexing and no delay time between channels. The result is precise channel balance. virtually total channel separation, extremely flat frequency response and more dynamic range.
The combination of the digital filter and selected D- to A-converter ensures the highest possible performance level. Precision-engineered 3rd-order analogue filters then provide the final grooming for the output signal.
Balanced, direct and variable analogue outputs
The choice of outputs caters for every application. And all outputs are protected from switching noise by two-stage muting.
The professional-standard balanced output uses the same output transformers as are fitted in Philips Professional CD Players. Studio requirements to ensure the highest possible performance.
The direct output avoids all non-essential switching In the signal path, thus eliminating all possible noise at the analogue amplifier input. The proper solution for sound purists. The variable output delivering 4 Vr.m.s. (maxi. makes it possible to set the exact level required at the power amplifier. Thus, the DAC 960 can function as a high-grade. audiophile pre-amplifier.
Headphone amplifier with volume control
A high-grade headphone amplifier with volume control provides the facility for direct Personal listening or source monitoring.
Absolute phase control
For the variable and headphone outputs. any phase inversion which may have arisen in the signal path can be corrected by the Absolute Phase control - a feature that ensures proper harmony In vocal and choral works.
Studio-quality engineering for the highest possible sound quality
To reach the ultimate n digital audio performance, the engineering of the DAC 960 is of the highest, studio-style quality, both mechanically and electrically.
Three completely separate power supplies. each with its own magnetically screened transformer, drive the digital input output circuitry, the D-to-A converter and the analogue circuits. This technique prevents any possibility of Interaction between the different circuit functions.
For the analogue circuits, the most sensitive to power supply variations, a high efficiency. heavy duty toroidal transformer is used. To ensure the highest immunity to vibration and resonance. the chassis is a diecast component weighing 2 kg. and the 'skin-plated' top cover has been acoustically damped.
The solid 3 mm thick base plate on big, shock absorbing feet contributes to this. Earth resistance can cause small leakage currents, which may create noise in the output signal. It is kept to an absolute minimum by copper plating the steel rear plate. and by using copper or bronze plated fixing screws to ensure good earth connections at the sub-assemblies.
Gold plated cinch terminals ensure low contact resistance and thus maintain the purest possible digital and analogue stereo signals. Particular emphasis has been laid on component quality. suitability and adequate rating for each specific function. The discrete components in the D/A circuitry and the 3rd order low-pass filters have been carefully selected for their 'audiophile' characteristics. Copper neat sinks ensure the best heat conduction and minimum sensitivity to mains frequency resonance.
The large-capacity ceramic-powder electrolytic capacitors for the power supplies are specially designed for top audio performance, and checked in the most severe listening tests.